Fed Ex or UPS.
I had packages shipped ahead to Pictou during our Down East cruise. It was a comedy of errors. I had called the marina for a reservation about 2 weeks ahead, asked them specifically for a shipping address to have a package sent, told them the package would arrive before we did, and if they could hold it. Long story short, the kid on duty when the package arrived thought it was a scam, refused the delivery, and when we arrived, did not have a slip for us, vaguely remembered something about the conversation earlier, but was pretty air-headed. I was able to call Fed Ex, intercept the package before it got to the airport, and they re-delivered it- to the wrong address, on a Friday. No Saturday delivery, extended our stay 3 days to get the package (electronic CHS charts that I had to buy and have shipped from Baltimore!).
The take-away we learned is that if you want to have something shipped ahead, ride herd on it. Follow progress and make sure you follow up with phone calls or email to insure someone knows what's going on. Many marinas are accustomed to receiving parcels for boaters, and they take it in stride. Some others, not so much, particularly those in more off-the-beaten path locales.